Once you've beat the game, you can go on a treasure hunt and look for one specific item in each scene - and fill up these shelves. 

Gorgeous game. 

I guess my job isn't all bad. While pursuing my target, I get to attend a masked party. 

I just had to take a screenie of this - it's so neat looking. 

Man, I'm just going all over the place. Now I'm in Venice. Am I sure I'm not chasing Carmen Sandiego?